The present invention relates to a steering column apparatus to be installed in a motor vehicle and particularly to a steering column apparatus equipped with a tilt position adjusting function for adjusting the position of the steering wheel and an impact energy absorbing mechanism at a secondary collision by the driver against the steering wheel.
US Patent Application Publication No. 2009/0218801 discloses such a steering column apparatus equipped with a tilt position adjusting function for adjusting the position of the steering wheel in the upward and downward directions and an impact energy absorbing mechanism at a secondary collision by the driver against the steering wheel.
This steering column apparatus is equipped with (a) a tilt jacket that is fixed to a vehicle attachment bracket through a tilt shaft to be adjustable in the upward and downward directions, (b) an upper jacket fixed to the tilt jacket to be compressible in the axial direction, and (c) an energy absorbing mechanism provided between the tilt jacket and the upper jacket. The upper jacket is moved in the axial direction relative to the tilt jacket in order to absorb the impact energy at the collision.
In this steering column apparatus, shaped wires are used as members for conducting energy absorption. Each wire is generally U-shaped. Bent base portion of the wire is engaged with an end surface of the tilt jacket. A free end of the wire, opposite to the bent base portion, is inserted into a hole of a distance bracket of the upper jacket.
Japanese Patent Application Publication 2005-219641 discloses a steering column apparatus using a wire 71 as an impact energy absorbing member at the secondary collision. The wire 71 is provided between a tilt bracket 3 supporting a column 4 and a vehicle body attachment bracket 2 and is folded at a center base portion into two halves. The wire 71 is fixed at the center base portion to a single bolt 62 provided on the side of the tilt bracket 3 and is wound around a pair of drawing bolts 72, 73 at its two portions toward its ends. The bolt 62 is guided into a guide groove 61. At the secondary collision, when the tilt bracket 3 together with the column 4 is detached from the vehicle body attachment bracket 2 and is moved forward, the bolt 62 is also moved forward to draw the wire 71. During this drawing, the wire 71 is continuously subjected to a plastic deformation (bending) at the drawing bolts 72, 73 to absorb impact energy of the secondary collision.